1. Field of the Invention
This invention relates to melt cutting and more specifically it relates to an improved process for the melt cutting of ethylene polymers.
2. Description of the Prior Art
The use of surfactants is wide spread in many applications. For example, ethylene oxide and propylene oxide copolymer surfactants are disclosed in U.S. Pat. Nos. 3,422,049, and 3,432,483, as aiding the preparation of dispersions of polymers with particle sizes of below 10 microns to not greater than 25 microns and in U.S. Pat. No. 4,007,247 for the preparation of fibrils, i.e., short fibers having diameters less than 25 microns and preferably less than 10 microns. All three of these patents disclose water dispersion processes for polymer particle size reduction using high temperatures and pressures as well as high speed agitation and surfactants.
U.S. Pat. No. 3,528,841 deals with reducing the tackiness of polymer pellets by applying a small particle size (less than 10 microns) polyolefin powder dispersed in water on the surface of the soft, sticky polymer to reduce its tackiness. In the alternative, the polyolefin powder coating can also be applied to the polymer by tumbling or by airveying. The purpose of applying this coating is to facilitate getting the product through the drying and purge steps of the production process and to supply a free flowing product to the trade.
Chemical Abstracts digest 87:153195p, Vol. 87, 1977 p. 48, entitled "Agglomeration prevention during stream-stripping of solvents from rubber solutions" involves the use of a 1000-3000 molecular weight ethylene oxide/propylene oxide copolymer as a surfactant in a water/hydrocarbon solvent dispersion. Thus, a 20% solids butadiene rubber solution in hexane was steam-stripped in a 0.005 weight percent solution of the above surfactant in water. This mixture forms a dispersion (oil in water at about 5 to 6% solids) and establishes the particle size of the rubber crumbs (average diameter 3.7 mm). The surfactant's function is to make the two imcompatible phases, namely, hexane and water into one compatible phase. Steam stripping is used to obtain a single liquid (water) phase, ending up with an 8% solids slurry. The process involves forming a particle size in dispersion form from a solution of the rubber in a hydrocarbon solvent.